1,3-Dibromopropane → 5-(3-bromo-propoxy)-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-indole-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-hydroxy-indole-1-carboxylic acid tert-butyl ester (195 mg, 0.43 mmol, Example 5D) in 1,3-dibromopropane (2 mL) is added cesium carbonate (350 mg, 1.08 mmol). The resulting suspension is heated at 100° C. for 30 minutes. It is then filtered and concentrated. The residue is chromatographed through silica gel (ethyl acetate-n-heptane, 05:95 to 20:80 as eluant) to provide 103 mg (42%) of 5-(3-bromo-propoxy)-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-indole-1-carboxylic acid tert-butyl ester as a yellow glass. LC/MS: RT=4.38 minutes, 576.11 m/e.

Provenance & Evidence